Identification, p.p.i. code sorting and printing tube



April 25, 1961 w. R. DAWIRS 2,981,361

IDENTIFICATION, PPI CODE SORTING AND PRINTING TUBE Filed Aug. ,8, 1955 IN V EN TOR. WILLIS R. UAW/R5 2. I AT R/VEYS 2,981,861 Patented Apr. 25, 1961 Free IDENTIFICATION, P.P.I. CODE SORTING AND PRINTING TUBE Willis R. Dawlrs, 2667 Grandvlew, San Diego 10, Calif.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to a code sorter and printer P.P.I. tube and more particularly to a novel cathode ray tube capable of displaying standard plan position indication (P.P.I.), both standard P.P.I. and RI. simultaneously when used in combination with standard P.P.I. practices. Characters for personal identification are the result of codes sorted and used to choose a stencil character which is printed on the tube face in a location determined by the P.P.I. deflection coil.

Previously, P.P.I. character printing methods have utilized cathode-ray tubes with external circuity and deflection coils to form lissajous characters or use complex wave forms to form characters. In most instances, the P.P.I. must time share with the printing device or the printing was done on the back trace. The printing technique was complicated and required appreciable time, in the order of tens of microseconds.

The tube comprising the present invention provides for all code sorting, character forming, recentering, and plan positioning and indicating in a straightforward manner with a minimum of external equipment and circuitry. The tube comprises an electron gun, deflecting means to deflect the beam both vertically and horizontally in reindicative of the particular combination of deflection plate voltages, recentering means for bending the beam by an equal amount but in the opposite direction from that of the deflecting means, and an external P.P.I. magnetic deflection coil which serves the same purpose as when used with conventional P.P.I. radar. In operation, a friendly target presented on the face of the tube in P.P.I. will cause certain combinations of deflection voltages to be energized to print'an identifying number on the tube face in the location of the detected target. By leaving an aperture in the matrix, the tube may be used solely for P.P.I. without the character presentation identification. By disconnecting the P.P.I. magnetic deflection coil, the tube will print the identifying character in the center Another object is the provision of a tube capable of position printing of pulse train code desigpersonal identification (P.I.)-in plan position or provision of a cathode-ray tube printing, and P.P.I. presentation 6 displaying P.P.I. information; target identification information over the target area on P.P.I. display, identification information centered on the face of the tube or a .plurali-ty of identification symbols spaced over the face 6 of the tube as desire A still further object is the provision of a cathode-ray tube having a deflection system which will sort codes made up of a plurality of ON-OFF voltage combinations, deflect the electron beam through the corresponding character of a shaping mask, and selectively recenter the acterized beam on the face of the tube, or project it directly from the mask to the face. of the tube or further deflect the characterized beam by means of an external P.P.I. magnetic deflection coil as desired.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. 1 is a symbolic view of the tube; and

Fig. 2 is a perspective view of the character forming mask.

Referring now to Fig. 1 the vacuum tube envelope 11 has the base end sealed by electron gun base seal'12 of andard lead stem for connection of electron gun 13. The tube is stepped with a flanged deflection system base seal 14 to accommodate the deflection plate leads. The glass tubing extends beyond the deflection system and character mask to accommodate a rotatable P.P.I. deflection coil. Ahead of the deflection coil, the tube has the shape of a standard P.P.I. cathode-ray tube.

The deflection system comprises sets of deflecting plates, recentering deflection plates and an externally mounted rotary P.P.I. magnetic deflection coil 15. The first pair of horizontal deflection plates 16 in the code sorting deflection system are designed to have four units of horizontal deflection for a unit of deflection voltage. The

emitted from the electron 28 deflect one unit horizontally for a unit voltage applied Similarly, vertical deflection plates 29, 31, and 32 deflect vertically four units, two units and one unit respectively. Both the deflection plates and the recentering deflection plates are illustrated as single plates for simplicity of description. However, in the preferred embodiment they comprise a plurality of spaced interleaved strips more fully described in the application of Cash and Dawirs, Serial No. 527,182, filed August 8, 1955.

The stencil mask 24 with its associated anode cylinder 33 is best shown in Fig. 2. The mask is made of very thin metal with the characters engraved therethrough. The characters are spaced in columns and rows one unit apart so that the electron beam will pass through a different character forming slot for each unit of vertical or horizontal deflection. The charactaers occupy a square, are about .020" high and have .003" lines.

the same purpose as on P.P.I. radar.

the trace to brighten producing a target at a direction and range calibated on the tube face. In the case of the number printing for a code sorter printer P.P.I. tube designed for numbers only, the beam would be turned on only at a time of printing. This means that no trace would be visible until the time of printing; at that time a number would be printed at the range and bearing of the target and would be the number of the code originating the target. An example of operation is the case of an aircraft at 100 miles bearing 120'. The radar will send out a pulse of energy. The plane will pick up that signal and return a coded reply, any Code #3. The code will arrive a certain time after the initial pulse is sent. Upon arrival the code will be impressed upon the deflection plates 21 and 22 and oppositely to 31 and 32. Also at that time the beam will be gated on. The beam will deflect 3 units to #3, be formed, and then be recentered toward center of the tube face. The deflection magnetic coil will deflect the beam as though it were from a standard electron gun. At the moment of printing, the magnetic deflection will place the number 3 at a point on the CRT corresponding to 100 miles, bearing 120. at 100 miles and 120'. In another type of operation, the beam passes through the aperture in mask 24 and is deflected by the magnetic deflection coil as in conventional P.P.I. practice. Then, when the target aircraft energizes its associated identifying deflection plates, the electrostatic deflection system will choose a number, shape the beam, and substitute the number for the original target indicating spot on the tube during the short printing interval. Thus, it can readily be seen that the tube may be used for P.P.I. presentation, character printing or both in a variety of types of operations.

While the preferred embodiment has just been described, other modifications are operable. For example,

aperture through which said beam may pass, a selective deflection means for deflecting said beam from said path to pass through selected slots, said deflection system comprising a plurality of sets of horizontal deflection means and a plurality of sets of vertical deflection means, each of said sets having predetermined dimensions operable to deflect said beam in predetermined increments when a predetermined amplitude of signal is applied to one or more of said sets of beam deflection means, a second deflection system disposed between said beam character forming means and said electron beam receiving means, said second deflection system having a different set of deflection means corresponding to each set of deflection means in said first set of deflection means and having the same deflection sensitivity to deflect said beam back to its original path upon applying said predetermined signal in reverse polarity, and external deflection means for radially and angularly positioning said beam on said receiving means.

2. In a code sorting and printing tube, in combination, a vacuum sealed envelope, electron beam receiving means at one end thereof, means opposite said receiving means for projecting an electron beam thereto, beam character forming means positioned across the path of said beam said beam character forming means having character forming slots through which said beam may pass, a first deflection system for deflecting said beam to pass through At the echo return time, number 3 will be printed the recentering plates may precede the mask so that the Y beam will be deflected and counter deflected before passing through the mask such that the beam, when it goes through the mask, is directed straight toward the center of the tube face. The deflection plates may take any form as long as the 1, 2, and 4 units of deflection is accomplished. More deflection plates may be used for a greater number of combinations as desired.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In a code sorting and printing tube, in combination, a vacuum sealed envelope, electron beam receiving means at one end thereof, means opposite said receiving means for projecting an electron beam thereto along a predetermined path, beam character forming means positioned across the path of said beam and having a central aperture at said path and character forming slots about said selected slots, said deflection system comprising a plurality of sets of horizontal deflection means and a plurality of sets of vertical deflection means, each of said sets having predetermined dimensions operable to deflect said beam in predetermined increments when a predetermined amplitude of signal is applied to one or more of said sets of beam deflection means, a second deflection sys tem disposed between said beam character forming means and said electron beam receiving means, said second deflection system having a different set of deflection means corresponding to each set of deflection means in said first set of deflection means and having the same deflection sensitivity to deflect said beam back to its original path upon applying said predetermined signal in reverse polarity, and external deflection means for radially and air gularly positioning said beam on said receiving means, said beam character forming means comprising a thin metallic sheet having an aperture therethrough through which said beam normally passes when not deflected by said selective deflection means.

References Cited in the file of this patent UNITED STATES PATENTS 2,698,399 Orr Dec. 28, 1954 2,718,611 McNaney Sept. 20, 1955 2,728,873 McNaney Dec. 27, 1955 2,735,956 McNaney Feb. 21, 1956 2,769,116 Koda et al Oct. 30, 1956 2,790,103 McNaney Apr. 23, 1957 2,803,769 McNaney Aug. 20, 1957 OTHER REFERENCES Instruments, vol. 25, No. 4, April 1952, page 488.

Educated Tube Will Aid Air Defense, by Philip Klass, Aviation Week, November 15, 1954, pages 77, 78, 80, 84 and 86.

"The Type C 19K Characteron Tube and Its Applications to Air Surveillance Systems, by J. T. McNaney, IRE Convention Record (1955) part 5, pp. 31-36. 

